XSLT - Garmin GPX - gnuplot

Un Garmin donne la trace GPS suivante : AiguillesRouges.gpx

<?xml version="1.0" encoding="UTF-8" standalone="no" ?>
<gpx xmlns="http://www.topografix.com/GPX/1/1" creator="MapSource 6.16.3" version="1.1"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.topografix.com/GPX/1/1 http://www.topografix.com/GPX/1/1/gpx.xsd">
  
  <metadata>
    <link href="http://www.garmin.com">   
      <text>Garmin International</text>
    </link>
    <time>2019-07-28T08:08:05Z</time>
    <bounds maxlat="46.024869801476598" maxlon="6.926982309669256" minlat="45.935957757756114" minlon="6.771008670330048"/>
  </metadata>
  
  <trk>
    <name>Tracé actuel: 23 JUIL 2019 07:39</name>
    <extensions>
      <gpxx:TrackExtension xmlns:gpxx="http://www.garmin.com/xmlschemas/GpxExtensions/v3">
        <gpxx:DisplayColor>Black</gpxx:DisplayColor>
      </gpxx:TrackExtension>
    </extensions>
    <trkseg>
      <trkpt lat="45.936855375766754" lon="6.771008670330048">
        <ele>872.52999999999997</ele>
        <time>2019-07-23T05:39:31Z</time>
      </trkpt>
      <trkpt lat="45.936975907534361" lon="6.77103029564023">
        <ele>873.98000000000002</ele>
        <time>2019-07-23T05:39:42Z</time>
      </trkpt>
      ...etc...

gpx.xsl, un petit bout de code XSLT

<?xml version="1.0"?>
<xsl:stylesheet version="1.0"
        xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
        xmlns:gpx="http://www.topografix.com/GPX/1/1">
  <xsl:output method="text"/>
  <xsl:template match="/">
    <xsl:for-each select="gpx:gpx/gpx:trk/gpx:trkseg/gpx:trkpt">
        <xsl:value-of select="@lon"/>
        <xsl:text> </xsl:text>
        <xsl:value-of select="@lat"/>
        <xsl:text> </xsl:text>
        <xsl:value-of select="gpx:ele"/>
        <xsl:text>
</xsl:text>
    </xsl:for-each>
  </xsl:template>
</xsl:stylesheet>

Et sur Linux,

$ xsltproc gpx.xsl AiguillesRouges.gpx > AigRou.xyz

donne les coordonnées X, Y et Z en 3 colonnes :

6.771008670330048 45.936855375766754 872.52999999999997
6.77103029564023 45.936975907534361 873.98000000000002
6.771165663376451 45.937128961086273 876.38
6.771242022514343 45.937253851443529 877.34000000000003
6.771263061091304 45.93731545843184 877.34000000000003
6.771297678351402 45.937489299103618 879.25999999999999
etc...

Qu'il suffit de traiter avec le script gnuplot suivant :

gnuplot << END
set term png size 1200,900
set grid xtics ytics ztics
set output 'AigRouXYZ.png'
splot "AigRou.xyz" with lines
set output 'AigRouXY.png'
plot "AigRou.xyz" using 1:2 with lines
set output 'AigRouZ.png'
plot "AigRou.xyz" using 3 with lines
END

pour obtenir les graphes suivants :